| ( | 55 | − | Y | ) | ÷ | ( | Y | − | 5 | ) | = | 2 | ÷ | 3 |
| 方程两边同时乘以: | ( | Y | − | 5 | ) |
| ( | 55 | − | Y | ) | = | 2 | ÷ | 3 | × | ( | Y | − | 5 | ) |
| 55 | − | Y | = | 2 | ÷ | 3 | × | ( | Y | − | 5 | ) |
| 55 | − | Y | = | 2 | ÷ | 3 | × | Y | − | 2 | ÷ | 3 | × | 5 |
| 55 | − | Y | = | 2 3 | Y | − | 10 3 |
| - | Y | − | 2 3 | Y | = | - | 10 3 | − | 55 |
| - | 5 3 | Y | = | - | 10 3 | − | 55 |
| - | 5 3 | Y | = | - | 175 3 |
175 3 | = | 5 3 | Y |
5 3 | Y | = | 175 3 |
| Y | = | 175 3 | ÷ | 5 3 |
| = | 175 3 | × | 3 5 |
| = | 35 | × | 1 |
| Y | = | 35 |